1. Field of the Invention
This invention relates to a method and apparatus for extracting useful biological trace constituents from urine through use of adsorbent filters placed in the gravity flow line between a flushless urinal and the holding tank of a portable toilet.
2. Prior Art
Human urine contains small percentages of a variety of proteins and especially enzymes which have commercial value, usually as pharmaceuticals. For example, the enzyme Urokinase, which is present in trace percentages in human urine, is widely used as an anti-clotting agent for blood and in connection with treatment for cancer because of its ability to dissolve the fibrin growths which sometimes sheath carcinogenic cells. Most of the commercial supply of Urokinase is now derived from urine by the collection of urine from paid donors who regularly visit central collection stations. Within a few hours of being collected the urine is transported to a central processing station where it is intermixed with adsorbents that attract the large protein molecules of interest. The collected proteins are then eluted off the adsorbents and the extract is processed and purified to derive the Urokinase or other commercially useful proteins. U.S. Pat. No. 3,755,083 discloses a process of this type.
Urokinase enzymes rapidly degenerate at normal collection temperatures so that it is necessary to process the urine as soon as possible after it is collected. The resulting collection and processing costs and the low percentage of Urokinase contained in urine result in a very high unit cost, severely limiting pharmaceutical use of the material.
As a more economical alternative to this process of collecting quantites of urine and then delivering them to a processing station, U.S. Pat. No. 3,711,377 to Sloane discloses a Urokinase collection process employing a tray filled with an adsorbent and adapted to be supported within the urinal proper so that a male donor may direct a urine stream onto the adsorbent. The tray is designed so that it rests in the urinal so that flushing water or chemicals do not contact the adsorbent but rather flush the surface of the urinal and the drain but not the adsorbent. This arrangement presents a number of disadvantages including the need for cooperation from the donors so that the urine passes through the adsorbent and the problems produced by the odors emanating from the unflushed filter. Cigarette butts and other debris thrown into the urinal may also contaminate or cause disassociation of the collected proteins.
British Pat. No. 1,308,727 discloses an arrangement in which an adsorbent containing filter is placed directly in the drain pipe connecting a conventional urinal to a sewer. This insures that urine voided into the urinal will pass over the adsorbent but expose the filter directly to the flow of flushing water and disinfecting chemicals placed in the urinal and makes frequent collection of the adsorbent difficult and expensive.